The present invention relates generally to electronic circuits, and more particularly, to a voltage regulator.
Integrated circuits (ICs) such as system-on-chips (SoCs) and application specific integrated circuits (ASICs) integrate various analog and digital components (hereinafter “electronic components”) on a single chip. The electronic components require a stable supply voltage for performing various operations. ICs include voltage regulators for regulating supply voltage. Voltage regulators reject noise injected into a supply voltage from a voltage source and provide regulated output voltage signals to the electronic components.
A gate driver is an example of an electronic component. The gate driver is connected to the voltage regulator and receives the regulated output voltage signal. The gate driver provides a gate driver signal that controls the switching operation of an external transistor, which in turn drives other electronic components. For efficient transistor switching, the gate driver needs a transient current to ramp up and down the voltage level of the gate driver signal within a very short time span, e.g., 10 nanoseconds (ns). However, the voltage regulator does not generate or provide a transient current to the gate driver. A known solution to overcome this problem is to use a capacitor with the voltage regulator to provide the transient current to the gate driver.
FIG. 1 shows an integrated circuit 100 that includes a conventional voltage regulator 102 and a gate driver (GD) 104. The voltage regulator 102 is connected to a voltage supply 106 by way of first and second pins 108a and 108b for receiving a first supply voltage (VBAT), and has an output terminal for providing an output voltage signal (VOUT) at a third pin 108c. The voltage regulator 102 regulates a voltage level of the output voltage signal (VOUT) to a desired voltage level. An external compensation capacitor 110 is connected to the voltage supply 106, and to the voltage regulator 102 by way of the third and second pins 108c and 108b, respectively.
The gate driver 104 is connected between the output of the voltage regulator 102 and one end of the supply voltage 106, and has an input terminal that receives an enable signal (ENABLE) and an output terminal that provides a gate driver signal (GDS). The GDS is connected to the gate of an external transistor 112 by way of a fourth pin 108d. The drain of the external transistor 112 is connected to a second supply voltage (VDD), and a source terminal is connected to the voltage supply 106, and to the voltage regulator 102 by way of the second pin 108b. The source terminal of the transistor 112 also is connected to one end of the compensation capacitor 110.
The output voltage signal (VOUT) is provided to the gate driver 104 and the compensation capacitor 110. The output voltage signal (VOUT) charges the compensation capacitor 110. When the compensation capacitor 110 is charged, the gate driver 104 receives a transient current from the compensation capacitor 110 for quickly increasing and decreasing the voltage level of the gate driver signal (GDS), which turns ON the transistor 112. Thus, the gate driver pulls the current out of the supply, which is generated by the voltage regulator and the external capacitor, so the voltage regulator provides DC regulation and the external capacitor provides the transient current. One drawback, however, of this solution is the necessity of the third pin 108c for connecting the voltage regulator to the external compensation capacitor 110.
Another solution is to integrate the compensation capacitor 110 into the integrated circuit 100 to eliminate the need for the third pin 108c. However, this increases the complexity, die area, and cost of the IC 100.
Therefore, it would be advantageous to have a voltage regulator that eliminates the need for a compensation capacitor to provide transient current to a gate driver, without significantly increasing the complexity or die area of the integrated circuit.